Joist-bridging.



' P. E. BERTRAM. V

JOIST BRIDGING. APIQPLIOATION FILED JUNE 13 'Patnted Apr. 20, 1909.

a 2d a l 7 a QWitnwoeo I PAUL E. BERTRAM, OF CRYSTAL LAKE, ILLINOIS.

JOIST-BRIDGING.

Specification of Letters Patent.

" Patented April 20, 1 09.

Application filed June 13, 1908. Serial No. 438,382.

To all whom it may concern: 7

Be it known that I, PAUL E. BERTRAM, a citizen of the United States, residing at Crystal Lake, in the county of McHenry and State of Illinois, have invented new and useful Improvements in Joist-Bridging, of which the ollowing is a specification.

This invention relates to improvements in joist-bridgings, the object of the invention being to provide a metallic joist-bridging which is simple of construction, strong, durable and eflicient in use and inexpensive of production, and which may be quickly and conveniently applied to the joists.

In the accom anying drawing illustrating the invention, igure 1 is a vertical transverse section through adjoining joists showing the a plication ofthe bridging. Fig. 2 is a top pan view of the same. Fig. 3 is a perspectlve view of one of the bridge bars.

In carrying my invention into ractice, I provide metallic bridge bars whic are employed in pairs and crossed to form a bridge of X-sha e between the ad'oining joists. Each of t ese bars-1 is of T- orm in crosssection, its flanges 2, constituting one of its elements, and its web 3 constituting its other element, being arranged at right angles to each other. The web element 2 is extended and bent at right angles at one end to form an attaching arm 4 having an opening 5 for the passage of a screw or other suitable fastening device, while the adjacent end of the element or web 3 terminates in line with the inner end of said arm to provide a bearing shoulder 6. The opposite end of the element 2 is pro erly shaped to form a bearing shoulder 7 w 'ch terminates short of the adjacent end of the web 3 which extends beyond the same and is properly shaped to form a penetrating spur or point 8. By this construction a simple, strong, durable and inexpensive type of bridge bar is provided.

In the application of the bars to thejo1sts 9 to form a bridging, the bars are arranged between the joists in the manner shown in Figs.'.1 and 2, the spur 8 being inserted into one joist, while the arm 4 is fastened by a screw or other securing device 10 to the other joist, the bar being sodisposed that the shoulders 6 and 7 bear directly against the sides of the joists. As a result of this construction and arrangement of the bars, an exceedingly strong and durable bridging is formed. By providing a s ur atone end which is adapted to be embedded in one joist and an attaching arm at the other end which is adapted to be secured to the other joist, but a sin le screw or other fastening is required to e driven or applied and the angular cross-sectional form of each bar and the arrangement of the shoulders 6 and 7 insure the production of a bar of great strength and its application to the joists in a substantial manner.

Havin thus fully described the invention, what is c aimed as new is 1. In a joist-bridging, a metallic bridgebar of angular form in cross section, providing elements arran ed at ri ht angles to each other, one of said e ements eing provided at one end of the bar with a bearing shoulder and at the other end of the bar with a enetrating spur, and the other element eing provided at one end of the bar with an attaching portion adjacent to said shoulder and at the other end of the bar with a bearing shoulder adjacent to said spur.

2. In a joist-bridging, aT-shaped metallic bridge bar, one element of which is provided at one end with a bearing shoulder and bent at its opposite end to form an attaching arm, and the other element of which is provided w th a penetrating spur projectin'g beyond sa1d shoulder and with a bearing shoulder adjacent said attaching arm.

3. In a joist-bridging, a bridge bar of T- form providing elements arranged at right angles to each other, one of said elements having at one end a bearing shoulder and bent at its opposite end to form an attaching arm, and the other element having at one end a s ur projecting beyond said shoulder.

11 testimony whereof I affix my signature in presence of two witnesses.

PAUL E. BERTRAM.

I 'Witnesses A. J. THOMPSON, W. B. HUFFMAN. 

